三一三十一

sānyīsānshíyī ㄙㄢ ㄧ ㄙㄢ ㄕˊ ㄧ

    • to divide something equally into three shares

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Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
three into one: three, with one left over (thirty-one)
Meaning
From an abacus division rhyme, originally 三一三剩一. It means dividing something equally into three shares.

Sources